Research in the area of cognitive psychophysiology of classical conditioning attempts to identify and index explanatory and interpretive processes in terms of the behavior of certain physiological responses. Among these indices, the galvanic skin response (GSR) occupies an historically dominant and preminant position. Even so, the characteristics of this response system have received only limited study. While researchers have relied heavily on amplitude and frequency measures of the response, the temporal aspects of the GSR have been relatively ignored. Recent research has uncovered the possibility that the temporal and amplitude dimensions of the response system may be independent. Moreover, analysis within the temporal dimension indicates a complex set of factors which are differentially sensitive to qualitatively different cognitive states. For these reasons, important theoretical and empirical conclusions based only on amplitude and/or frequency factors are not only incomplete, but, more importantly, may seriously distort the actual information contained within the response system. The major objective of the research proposed is to provide a comprehensive analysis of response measures and their interrelationships in a variety of experimental situations and in populations differing in degree of cognitive capacity and utilization. In addition, changes in the interrelationships between response measures will be studied as dependent variation for the first time. The proposed research will use a variety of multivariate statistical analyses making possible the study of sets and combinations of response measures as dependent variation. These procedures will make possible the determination of the relative contribution of different response characteristics in the measurement of empirical phenomena. These results will guide further studies in developing techniques for differentiating the role of cognitive processes in the multiple response phenomenon characteristic of human classical conditioning.